Tenable Nessus

What it is

Tenable Nessus is a commercial vulnerability assessment scanner from Tenable, Inc. It is used to discover hosts and services, check for missing patches and misconfigurations, and produce findings that teams can prioritise and remediate. A limited free Essentials licence exists for non-commercial learning and small home use.

What it helps with

- Scanning operating systems, network devices, hypervisors, databases and related assets for known vulnerabilities
- Applying configuration and compliance audit templates on commercial editions
- Scoring and grouping findings (including CVSS and related prioritisation signals described on the product pages)
- Producing configurable reports for IT and security stakeholders
- Supporting point-in-time assessments for consultants, pentesters and internal teams on Professional / Expert licences
- Extending into web application, external attack-surface and infrastructure-as-code checks on Nessus Expert where licensed

Who it's for

Security practitioners, consultants and IT teams performing authorised vulnerability assessment. Essentials / Essentials Plus target learners, educators and non-commercial hobby use with hard IP limits. Production and consulting use requires commercial licensing.

Worth knowing

Official documentation and product pages distinguish Essentials (free, non-commercial, limited) from Professional and Expert. Nessus also underpins broader Tenable exposure-management offerings (for example Tenable One / Vulnerability Management cloud), which are separate products. Use only on systems you own or are explicitly authorised to test. Plugin feeds and feature sets differ by licence; verify current limits on tenable.com before purchase.